1. Field of the Invention
The present invention relates to personal mobility vehicles primarily for use by disabled persons. More specifically, the present invention relates to a personal mobility vehicle incorporating a seat assembly capable of being swiveled in a substantially horizontal plane, as well as, being capable of being raised and tilted so as to put a rider into an at least partially elevated stance.
2. Description of the Prior Art
Personal mobility vehicles, such as wheelchairs and carts, are well known in the art for providing disabled persons with a means for transport. Various mechanisms and functionality have been incorporated into personal mobility vehicles to increase the ability of disabled persons to perform various tasks.
Wheelchair-type personal mobility vehicles are typically characterized by a relatively short wheel base and a narrow width, so that they can be used in interior spaces where they must fit through narrow doorways and negotiate in small spaces. Given these severe size constraints, powered wheelchairs typically have a limited range and a rather low top speed making them ill-suited to use outdoors when covering relatively long distances. Furthermore, because of their very short wheelbase, they are not well suited to travel over irregular surfaces such as lawns and dirt paths, which may include steep grades that would cause the wheelchair to become unstable.
Because they typically do duty as leg replacements for disabled persons, wheelchairs have been designed that attempt to minimize the limitations of a disabled person in his or her day to day activities. As mentioned above, one feature known to be incorporated into certain wheelchairs is a tilting and/or lifting seat as is described in U.S. Pat. Nos. 4,076,304; 5,346,280; 5,363,934; 5,772,226; 6,125,957; 6,192,533; and 6,231,067. The seats in each of these wheelchairs is described as elevating the user into a xe2x80x9cstandingxe2x80x9d position. In all but U.S. Pat. No. 5,363,934, the seat bottom""s front edge is tilted downwardly while the seat back is raised and maintained at a substantially vertical orientation. Three of the described chairs (U.S. Pat. Nos. 5,346,280; 4,076,304; and 6,192,533) require stabilizer legs that contact the ground when the user is in the xe2x80x9cstandingxe2x80x9d position to prevent the wheelchair from inadvertently tipping over. In general the very narrow track of the described wheelchairs, with or without stabilization would not be acceptable for use in tasks involving substantial dynamic movement, such as swinging a golf club. Furthermore, given the short wheel base, these vehicles would be particularly unstable on sloped ground, especially when combined with the dynamic movement of the user.
None of the wheelchairs described in the aforementioned patents permit the seat to be swiveled. It is to be appreciated that because of the short wheel base and track width of wheelchairs that swiveling the seat and subsequently raising the seat into a xe2x80x9cstandingxe2x80x9d position would almost assuredly make the wheelchair and user unstable and subject to tipping.
Cart-type personal mobility vehicles are on the other hand more suitable for providing mobility over irregular surfaces as they have longer wheelbases and track widths, providing for greater stability than wheelchairs. Furthermore, because of their increased sized they can utilize larger motors and larger battery packs which provide for a greater range of travel. Because carts are typically too large for indoor use, they are typically designed around specific outdoor uses. One use of cart-type personal mobility vehicles includes transporting disabled and other persons around a golf course, where the distances traveled and the uneven terrain make wheelchairs impractical. It is also to be appreciated that the relatively high pressure exerted by the wheelchair""s points of contact with the ground makes it un-usable on a golf course due to the likelihood of either damaging the grounds or becoming stuck.
Since cart-type personal mobility vehicles typically include a steering wheel or steering tiller, several carts have been described in U.S. Pat. Nos. 5,341,894; 5,727,642; and 5,950,751 that swivel the rider to the side, wherein the rider can more easily perform activities that require him to be facing in the direction of the task being performed. It is of particular note that all of the carts described in the aforementioned patents relate to providing both a transport means and a platform from which a disabled person can participate in golf. It is to be appreciated that neither of the described carts permit the seat to be raised and tilted as to put the rider into a xe2x80x9cstandingxe2x80x9d position.
A mobility vehicle for use by disabled persons is described. In one embodiment, the mobility vehicle comprises a chassis or framework coupled with a wheeled drive system. A seat assembly is pivotally attached to the chassis for swiveling movement about an axis of rotation. The seat assembly includes a seat bottom, a seat back and a tilt mechanism coupled to the seat back and bottom. The tilt mechanism is configured for moving the seat assembly between a first position wherein the seat bottom is generally horizontal and a second position, wherein the seat bottom is tilted to an angle relative to horizontal. In both tilt positions the seat back is maintained in a generally vertical orientation. In variations of this embodiment, a releasable restraining mechanism is provided to hold the seat in one or more swivel positions, and a canopy is provided for shading the rider that retracts as the seat assembly is moved into its second position. Preferably, the tilting of the seat assembly is accomplished by a linear actuator that is attached to the seat back at one end.
In another embodiment, the mobility vehicle comprises a seat assembly incorporating a linear actuator and a four bar linkage to facilitate the tilting of the seat bottom and movement of the seat back is described. The seat bottom is moveable from a fully retracted position wherein the seat bottom is generally horizontal to a fully tilted position wherein the seat bottom forms an angle with a horizontal plane. Actuation of the linear actuator acting through the seat back and four bar linkage causes the seat bottom to tilt, while the orientation of the seat back relative to horizontal is maintained at a relatively constant angle.
In another embodiment, the seat bottom of the seat assembly is pivotally attached to a swivel frame of the seat assembly at its front edge such that the seat bottom is tilted by raising a rear edge of the seat bottom about a horizontal axis defined by the pivotal connection. In variations of this embodiment the seat back is raised in unison with the rear edge of the seat bottom, while the angle of the seat back does not change significantly.
In yet another embodiment, a mobility vehicle is described that incorporates a seat assembly wherein the seat bottom of the seat assembly can be both swiveled about a vertical axis and tilted to angles in excess of 25 degrees. By tilting the seat bottom, a person seated thereon can be moved from a sitting position to a standing stance.